Hydrothermally grown synthetic rubies crystallize slowly out of a solution (a mix of water and dissolved elements) that has been exposed to heat and pressure similar to the conditions on Earth under which the natural gem mineral grows. Synthetic gems have the same chemical, optical, and physical properties of their natural counterparts, but are a more cost-effective alternative to a natural gem.

Colors

Slightly Orangy Red, Red, Purplish Red

Ruby-synthetic-hydrothermal classification

CommonName

Ruby (Synthetic - Hydrothermal)

Species

Corundum

Variety

Hydrothermal Synthetic Ruby

Colors

Slightly Orangy Red, Red, Purplish Red

AlternateNames

Lab Created Ruby

GemstoneGroups

KeySeparations

magnification and RI, birefringence, pleochroism

ClassificationComments

Ruby-synthetic-hydrothermal chemistry & crystallography

ChemicalName

aluminum oxide

ChemicalFormula

Al2O3

Synthesis

hydrothermal

CrystalSystem

Trigonal

ChemistryClassification

Oxide

Nature

Synthetic

Crystallinity

Crystalline

ChemistryComments

Ruby-synthetic-hydrothermal optical properties

Transparency

Transparent - Opaque

Dispersion

Strength: moderate fire Value: 0.018

OpticalComments

RefractiveIndex

1.762-1.77 Tolerance:(+0.009/-0.005)

Birefringence

0.008-0.01

OpticCharacter

Uniaxial

OpticSign

Negative

PolariscopeReaction

Doubly Refractive (DR)

Fluorescence

SWUV: inert to weak red LWUV: weak to moderate red

CCFReaction

red

Pleochroism

Dichroic, moderate to strong orangy red and purplish red

Ruby-synthetic-hydrothermal characteristic physical properties

Hardness

9

CharacteristicComments

Streak

White

SpecificGravity

3.95-4.1 Typical:4

Toughness

Excellent

Inclusions

Look for chevron, wavy, zig-zag or mosaic growth patterns in hydrothermal synthetic ruby because stones might show growth zoning similar to natural ruby. Fingerprint like inclusions with 2-phase and 3-phase inclusions can be seen in stones. Sometimes flake like copper inclusions are visible in reflected light.